To snap the above image, Rosetta swooped about 1,965 miles (3,162 kilometers) above Lutetia's surface. The image is the highest-resolution photo taken of the space rock, located more than 270 million miles (440 million kilometers) away from Earth, between Mars and Jupiter. (Watch a video of Rosetta's flyby.)

The sharp edge visible above, at bottom, may be evidence that 81-mile-wide (130-kilometer-wide) Lutetia broke off from a "mother asteroid," said NASA space scientist Claudia Alexander, who led the United States' involvement in the Rosetta mission.

—Andrew Fazekas

Image courtesy ESA

Asteroid Flyby

Launched on March 2, 2004, the three-ton comet chaser Rosetta (shown in 2008 with asteroid 2867 Steins in an artist's conception) has made three flybys of Earth and one of Mars.

The flybys are intended to allow the craft to gain enough speed to reach its final destination in 2014: comet 67/P Churyumov-Gerasimenko, which completes an orbit of the sun every six years.

As the first craft intended for long-term exploration of a comet, Rosetta will intercept Churyumov-Gerasimenko in cold outer regions of the solar system. After dispatching a small lander to the surface of the comet's nucleus, Rosetta will orbit Churyumov-Gerasimenko for two years as it approaches the inner solar system.

Image courtesy ESA

Giant Crater

A 20-mile-wide (30-kilometer-wide) shallow crater (pictured)—with evidence of a possible rockslide on its floor—is seen in a detail of the highest-resolution photo of asteroid Lutetia to date.

Mission scientists also observed what may be large boulders precariously perched along the crater's rim—suggesting the asteroid may have a sizable gravitational pull.

"If the gravity is just right," NASA's Claudia Alexander said, the boulders should be loosely held to the surface. "And as the asteroid spins, they could even be rolling across the surface."

Image courtesy ESA

Lutetia Looms Into View

In the minutes before reaching asteroid Lutetia—and still tens of thousands of miles away—Rosetta snapped a series of pictures (above, a clockwise progression from farthest to nearest).

The asteroid didn't rotate much during the course of this photo session. The shifts in angle are due instead to the spacecraft's rapid movement as it swung by the asteroid.

Image courtesy ESA

Parting Shot of Asteroid Lutetia

Rosetta took a parting shot (shown) of Lutetia while about 25,000 miles (40,000 kilometers) from the asteroid on Saturday. Shortly thereafter, mission controllers put the probe to "sleep," beginning a long hibernation intended to save power.

During the two-hour Lutetia flyby, Rosetta captured about 400 pictures, each of which took about ten minutes to reach Earth.